I have still been reading multiple theories about the alternate timeline somehow being the future outcome for our Losties AFTER the Island.
I just want to remind everybody of a rather important comment made by the writers of Lost.... "The sidways timeline is NOT the future outcome for our Losties, it is an alternate reality happening in real time" (ie at the same time as the Island).
Therefore i believe this alternate world is how the lives of our Losties eventuate when they have exercised free will, without Jacob's or the Island's influence on their lives. This 'reset' happened when they exploded the bomb (it split the timeline in 2 and created 2 realities which are occurring in real time)!!!! I write this not as a 'new' theory, but to allow everbody to understand this point and stop wasting time with theories that are incorrect by assuming this (alt-world)is a future reality.